[19].Surah Maryam [Mary] : Ayat 83-84

Ayat 83. See you not that We have sent the Shayâtin (devils) against the disbelievers to push them to do evil.

Ayat 84. So make no haste against them; We only count out to them a (limited) number (of the days of the life of this world and delay their term so that they may increase in evil and sins).

[Tafseer] Sees thou not that We have set the Evil Ones on against the unbelievers, to incite them with fury? Under the laws instituted by Allah, when evil reaches a certain stage of rebellion and defiance, it is left to gather momentum and to rush with fury to its own destruction. It is given a certain amount of respite, as a last chance: but failing repentance, its days are numbered. The godly therefore should not worry themselves over the apparent worldly success of evil, but should get on with their own duties in a spirit of trust in Allah. So make no haste against them, for We but count out to them a (limited) number (of days). 

Hazrat Abdullah bin Masud (May Allah be pleased with him) reported: Messenger of Allah [SAWW](PBUH) said, "Never a Prophet had been sent before me by Allah to his people but he had, among his people, (his) disciples and companions, who followed his ways and obeyed his command. Then there came after them their successors who proclaimed what they did not practise, and practised what they were not commanded to do. And (he) who strove against them with his hand is a believer; he who strove against them with his heart is a believer; and he who strove against them with his tongue is a believer ; and beyond that there is no grain of Faith".

[Muslim Book 01, Chapter 21, Hadith # 081] 

Lesson : as mentioned above in Surah Maryam Ayat 84."We only count out to them a (limited) number (of the days of the life of this world and delay their term so that they may increase in evil and sins). This Hadith contains a very important prescription to prevent the Muslim society from all things which are forbidden in Islam. So long as Muslims adhered to it and ceaselessly and fearlessly performed their obligation of enjoining the right and forbidding the wrong, their society was largely safe from many evils and sins.